Quartz (Druzy or Chalcedony variant)
Silicon Dioxide (SiO2)
mineral
Category
Sedimentary Rock (Possibly Composed Of Various Minerals)
Browse sedimentary rock (possibly composed of various minerals) specimens identified by the Rock Identifier community.
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Weathered quartz-rich metamorphic rock, likely quartzite
Quartzite; predominantly quartz (SiO₂), possibly with feldspar, mica, and iron-oxide staining
metamorphic
Slate
Foliated Metamorphic Rock (composed mainly of clay minerals or micas)
metamorphic
Piddock-bored Mudstone
Lutite (Siltstone or Mudstone) with Pholad borings
sedimentary
Coquina
Coquina (Bioclastic Limestone)
sedimentary
Limestone
Calcium carbonate (CaCO3)
sedimentary
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral
Tektite
Impactite (Natural Silicate Glass)
meteorite
Weathered limestone or calcareous fossil fragment
Calcite-rich carbonate rock (CaCO₃), possibly fossiliferous limestone
sedimentary
Sandstone (Red/Brown Variety)
Arenite (composed primarily of SiO2 with Fe2O3 iron oxide inclusions)
sedimentary
Jasper Pebble
Microcrystalline Quartz (SiO2)
sedimentary
Red Jasper (Chert)
Silicon Dioxide (SiO2) with impure Iron Oxides
sedimentary
Basalt River Pebble
Mafic Volcanic Rock (Basalt)
igneous
Granite
Granite
igneous
Basalt
Extrusive Mafic Igneous Rock
igneous
Schist
Crystalline Schist (often containing Muscovite, Biotte, or Quartz)
metamorphic
Chert with Quartz Veining
Microcrystalline Silica (SiO2)
sedimentary
Fossil Snail
Gastropoda fossil
fossil
Sandstone (likely Arkosic or Lithic)
Clastic Sedimentary Rock (composed predominantly of sand-sized grains, 0.0625 to 2 mm)
sedimentary
Unidentified Small Rock
Unknown
undetermined
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Slate
Foliated Metamorphic Rock (primarily composed of Muscovite, Chlorite, and Quartz)
metamorphic
Fossilized Shark Tooth
Chondrichthyes (Class) fossil
fossil
Mica Schist
Mica Schist (composed mainly of Muscovite / Biotite, Quartz, and Feldspar)
metamorphic
Tumbled Stone
Silicon dioxide / Various silicates
mineral
Ironstone (Limonite/Hematite)
Ferruginous sedimentary rock (Fe2O3·nH2O / Fe2O3)
sedimentary
River Pebbles and Quartz
Mixed Igneous, Sedimentary, and Metamorphic Rocks (Silicon Dioxide SiO2 dominant)
mixed
Chert (variations include Chalcedony and Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Agate
Chalcedony (SiO2)
sedimentary
Mixed Gemstones and Minerals
Mixed Silicates and Oxides (Quartz/Amethyst, Aventurine, Sodalite, Chert, Jasper)
mineral
Granite Cobble
Felsic Intrusive Igneous Rock (composed of Quartz, Alkali Feldspar, and Plagioclase)
igneous
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Limonite (Ironstone Concretion)
Limonite: FeO(OH)·nH2O
sedimentary
Limestone
Sedimentary rock composed primarily of Calcium Carbonate (CaCO3)
sedimentary
Limestone
Sedimentary rock composed primarily of Calcium Carbonate (CaCO3)
sedimentary
Weathered metallic sulfide-bearing rock, possibly chalcopyrite ore
Likely chalcopyrite (CuFeS₂) in a weathered host rock; identification is uncertain from the photograph
mineral
Quartz with Inclusions
Silicon Dioxide (SiO2)
mineral
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Jasper (Yellow/Brown variety)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Coquina
Coquina (Bioclastic Limestone)
sedimentary